This invention relates generally to semiconductor devices and, more specifically, to a semiconductor device with a sinker contact region and a method of manufacturing the same.
In complementary bipolar technologies for high-precision high speed analog and mixed-signal applications, a sinker contact is generally used to reduce the collector resistance. In a standard process integration sequence, collector sinkers are realized by using high-energy ion implantation of p-type or n-type dopants into the collector epitaxy. Dopant activation and diffusion are then realized by a thermal step (e.g., furnace or rapid thermal anneal). The diffusion penetrates into the collector epitaxial layer to electrically contact the underlying buried layer.
One or two lithographic steps are necessary to selectively introduce dopants into the collector epitaxy. Furthermore, high-energy high-dose ion implant capability is used for higher voltage applications in which thick collector epitaxy is used to guarantee high breakdown characteristics.
The present invention provides a semiconductor device and method for manufacturing the same that substantially eliminates or reduces at least some of the disadvantages and problems associated with previously developed semiconductor devices and methods for manufacturing the same.
In accordance with a particular embodiment of the present invention, a method for manufacturing a semiconductor device includes forming a buried layer of a semiconductor substrate. An active region is formed adjacent at least a portion of the buried layer. A first isolation structure is formed adjacent at least a portion of the buried layer. A second isolation structure is formed adjacent at least a portion of the active region. A base layer is formed adjacent at least a portion of the active region. A dielectric layer is formed adjacent at least a portion of the base layer, and then at least part of the dielectric layer is removed at an emitter contact location and at a sinker contact location. An emitter structure is formed at the emitter contact location. Forming the emitter structure includes etching the semiconductor device at the sinker contact location to form a sinker contact region. The sinker contact region has a first depth. The method may also include forming a gate structure. Forming the gate structure includes etching the sinker contact region thereby increasing the first depth of the sinker contact region to a second depth.
In accordance with another embodiment, a semiconductor device includes a buried layer of a semiconductor substrate and an active region adjacent at least a portion of the buried layer. A first isolation structure is adjacent at least a portion of the buried layer, and a second isolation structure is adjacent at least a portion of the active region. A base layer is adjacent at least a portion of the active region, and a dielectric portion is adjacent at least a portion of the base layer. The semiconductor device includes an emitter structure adjacent at least a portion of the base layer and a sinker contact region of the semiconductor substrate. The sinker contact region is formed adjacent at least a portion of the second isolation structure when the emitter structure is formed. The sinker contact region may have a depth of approximately 0.3 to 0.6 microns.
Technical advantages of particular embodiments of the present invention include a method of manufacturing a semiconductor device with a sinker contact region that requires less lithographic steps to complete the manufacturing process since the sinker contact region is formed when the dielectric layer is defined. Accordingly, the total time it takes to manufacture the semiconductor device and the labor resources required are reduced.
Another technical advantage of particular embodiments of the preset invention includes a method of manufacturing a semiconductor device with a sinker contact region that does not require high energy ion implantation to make the electrical contact between a collector contact and the buried layer since the collector contact can be formed within the sinker contact region. This can reduce the amount of time it takes to manufacture semiconductor device. It can also decrease the potential for contamination of critical devices or structures since the use of high energy implants can lead to such contamination during the manufacturing process.
Other technical advantages will be readily apparent to one skilled in the art from the following figures, descriptions and claims. Moreover, while specific advantages have been enumerated above, various embodiments may include all, some or none of the enumerated advantages.